Universal knife block for tufting machines

ABSTRACT

This disclosure relates to knife blocks for supporting the cutting knives in cut pile tufting machines and includes an adjustable knife clamping means which will accommodate a variety of sizes of cutting knives. The knife block generally comprises an elongated rectangular knife supporting body having a truncated knife supporting cavity and means for clamping a knife therein such that a knife supported in the cavity will be tightly wedged therein.

United States Patent [191 Bonner, Sr.

[ UNIVERSAL KNIFE BLOCK FOR TUFTING MACHINES [75] Inventor: Alvin T. Bonner, Sr., Chattanooga,

Tenn.

[73] Assignee: The Singer Company, New York,

[22] Filed: May 8, 1972 [21] Appl. No.: 251,128

52 US. Cl ..112/79 R, 30/329, 83/700, 29/96 51 Int. Cl. ..l)05c 1 5 /24 58 Field0fSearch...112 /79 R,7'9A;2'6"6,"1"2'9,130; 30/329, 332, 333, 296 R; 83/698, 699, 700; 29/96 [56] References Cited UNITED STATES PATENTS 306,257 10/1884 Johnson 29/96 Jan. 29, 1974 567,685 9/1896 Nelson 29/96 2,849,787 9/1958 Hertel 29/96 3,277,852 10/1966 Card 112/79 R 3,604,379 9/1971 Cobble 112/79 R 3,386,398 6/1968 Cobble, Sr. et al 30/329 X Primary Examiner-James R. Boler Attorney, Agent, or F irm-Marshall J. Breen,

Chester A. Williams, J r. & Julian Falk 5 Claims, 6 Drawing Figures UNIVERSAL KNIFE BLOCK FOR TUF TING MACHINES GENERAL DESCRIPTION OF THE INVENTION Knife blocks for tufting machines known in the prior art are generally of a construction such that they accommodate only one or a very limited range of sizes of knives. When a tufting machine is converted from one use to another, such as from tufting heavy yarns to light yarns or yarns of different composition, it may be necessary to change the knife blocks for supporting the different size cutting knives.

It is a prime purpose of the present invention to provide a knife block which will accommodate a wide range of sizes of cutting knives thereby eliminating the need for changing the knife blocks when it is desired to use a different size knife. The invention is generally carried out by providing a two section or two piece knife block construction with each piece having a wedge shaped or triangular groove provided therein at its knife engaging side which when in assembled condition provides a truncated-shaped knife supporting cavity. One of the pieces is provided with blind screwthreaded holes adjacent each end of the piece and the other is provided with through holes for receiving screws therethrough for threading into the blind screwthreaded holes. Thus when a knife is received in the truncated cavity the pieces may be tightened or clamped together by the screw means and the knife will be clamped therebetween. Because of the shape of the cavity, knives of many varying widths and thicknesses may be used since the wedging and clamping effect of the surfaces of the cavity will serve to securely clamp the knife in place.

Accordingly, it is one object of the invention to provide a novel and improved knife block for tufting machines.

It is another object of the invention to provide a novel and improved knife block for tufting machines which will accommodate a large variety of cutting knives.

It is a further object of the invention to provide a novel and improved knife block for tufting machines which will accommodate a plurality of sizes of cutting knives and is simple in use and construction.

Other objects and advantages of the invention will be best understood when reading the following detailed description of the invention along with the accompanying drawings in which:

FIG. 1 is a side elevational view of some of the tufting components of a tufting machine and illustrating the knife block of the invention;

FIG. 2 is a partial sectional view taken along line 22 of FIG. 1;

FIG. 3 is a partial sectional view taken along line 3-3 of FIG. 1;

FIG. 4 is a partial exploded perspective view of the knife block of the invention;

FIG. 5 is a top plan view showing one size knife in a clamped position; and

FIG. 6 is a top plan view showing a different size knife in a clamped position.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, a tufting machine hook or looper 10 is shown as being supported in a looper block 12 which is in turn supported by a block support 14. The

block support 14 is suitably bolted to a rock shaft 16 for rocking the looper 10 back and forth for picking up a loop of yarn from the needle (not shown) in a known manner. In cut pile machines the looper 10 is generally rocked into a position for cooperating with a knife mechanism in a timed relationship for cutting the loop of yarn to form cut pile.

In order to carry out this objective a cutting knife 18 is carried by a knife block 20 which in turn is supported on a rock shaft 22 for oscillating the knife back and forth into cutting engagement with the yarn on the looper. Such mechanism is well known in the art and no invention is alleged therein, although it should be understood that the present invention is not limited to use in the mechanism illustrated.

Referring now to FIGS. 2-6, it will be seen that the knife block 20 comprises a pair of generally rectangular pieces 24 and 26 each of which includes a triangular-shaped or wedge shaped cut-out or groove portion 28 and 30, respectively. The piece 26 further includes a lug 32 integral therewith for supporting the knife block in the rock shaft 22, as illustrated in FIG. 1. As further illustrated in FIGS. 2, 3 and 4, the cut-outs 28 and 30 may be each inclined from one side of their respective sides to the other so that a knife 18 supported therein will be at a desired angle relative to the cutting edge on the looper 10 for providing a scissor-like action therewith. Of course, it should be understood that the inclination of the knife may be varied or other means for adjusting the position of the knife relative to the looper provided.

In order to clamp the knife 18 into position in the knife block 20, the piece 26 is provided with blind screw threaded holes 34 and 36 which mate with through holes 38 and 40 in piece 24 when the knife block is assembled. Screws 42 are provided for threading into holes 34 and 36 through holes 38 and 40 so that the knife can be securly clamped in the knife block and so that the pieces 24 and 26 may be adjusted relative to one another for accommodating different size knives.

As shown in FIGS. 5 and 6, when the knife block is assembled the two wedge-shaped cut-outs 28 and 30 combine to form a truncated-shaped knife receiving cavity 44 having knife engaging surfaces 46, 48, 50 and 52. The surfaces 50 and 52 combine to form a substantially flat surface on which a flat surface of the knife rests. As the screws 42 are tightened in holes 34 and 36 the non-parallel surfaces 46 and 48 of the truncatedshaped cavity will engage edges on the knife 18 as illustrated, and will act in a wedging manner to clamp the knife in the block. As will be apparent the edges 46 and 48 can accommodate a knife edge substantially anywhere along their surface so that over-all the cavity 44 may accommodate a wide range of varying width and thickness knives. As shown in the drawing a relatively narrow width and thin knife can be accommodated therein, as shown in FIG. 5 as well as a wider width and thicker knife 18', as shown in FIG. 6.

Thus instead of requiring a change in knife blocks when changing knife sizes, all that is required in the present invention is that the screws 42 by loosened, the old knife slipped out, the new size knife slipped in and the screws re-tightened. Also it will be apparent that there are no small clamping elements to contend with as in the prior art devices and that the device of the invention is simple in construction and in use.

It will be apparent to those skilled in the art that various modifications and changes may be made without departing from the spirit and scope of the invention and it is not intended that the invention be limited except as defined in the appended claims.

What is claimed is:

1. A yarn loop cutting apparatus for a tufting machine including an elongated loop cutting knife of substantially rectangular cross-section, a knife block including a substantially rectangular knife supporting body, said knife supporting body having an elongated cavity extending the entire length thereof for receiving said knife, said cavity having a truncated shape with sloping side walls for wedging the substantially flat side walls of said knife therebetween and means for clamping said knife between the sloping side walls of said cavity such that different size knives can be accommodated in said cavity.

2. A yarn loop cutting apparatus as recited in claim 1 wherein said cavity extends in a direction parallel to a diagonal of said substantially rectangular knife supporting body.

3. A knife block for a tufting machine as recited in claim 1, wherein said body is comprised of two elongated sections with each section having an elongated wedge shaped cut-out therein such that when said two sections are assembled the elongated wedge shaped cut-outs form said elongated cavity.

4. A knife block for a tufting machine as recited in claim 3 wherein said two sections are adjustable relative to one another for accommodating and clamping different size knives in said cavity.

5. In a tufting machine having looper means for seizing loops from a yarn carrying needle and a cutting apparatus for cutting the loops of yarn seized by said looper means, said looper means including an oscillating looper having a substantially rectangular crosssection with one edge thereof forming a cutting edge, said cutting apparatus including a substantially rectangular cutting knife having a cutting edge disposed for cooperation with the cutting edge as said looper, means for initiating relative oscillating motion between said looper and said knife such that the cutting edges on said looper and said knife cooperate to cut a loop disposed on said looper, said cutting apparatus further including a knife supporting block having a substantially rectangular cross-section and having a truncated cavity disposed therein with the side walls of said cavity being disposed at an acute angle with respect to the base wall of said cavity, and means for clamping said substantially rectangular knife in said cavity with its end walls in clamping relationship with the side walls of said cavity whereby said knife is clamped in a wedging relationship with said cavity side walls. 

1. A yarn loop cutting apparatus for a tufting machIne including an elongated loop cutting knife of substantially rectangular cross-section, a knife block including a substantially rectangular knife supporting body, said knife supporting body having an elongated cavity extending the entire length thereof for receiving said knife, said cavity having a truncated shape with sloping side walls for wedging the substantially flat side walls of said knife therebetween and means for clamping said knife between the sloping side walls of said cavity such that different size knives can be accommodated in said cavity.
 2. A yarn loop cutting apparatus as recited in claim 1 wherein said cavity extends in a direction parallel to a diagonal of said substantially rectangular knife supporting body.
 3. A knife block for a tufting machine as recited in claim 1, wherein said body is comprised of two elongated sections with each section having an elongated wedge shaped cut-out therein such that when said two sections are assembled the elongated wedge shaped cut-outs form said elongated cavity.
 4. A knife block for a tufting machine as recited in claim 3 wherein said two sections are adjustable relative to one another for accommodating and clamping different size knives in said cavity.
 5. In a tufting machine having looper means for seizing loops from a yarn carrying needle and a cutting apparatus for cutting the loops of yarn seized by said looper means, said looper means including an oscillating looper having a substantially rectangular cross-section with one edge thereof forming a cutting edge, said cutting apparatus including a substantially rectangular cutting knife having a cutting edge disposed for cooperation with the cutting edge as said looper, means for initiating relative oscillating motion between said looper and said knife such that the cutting edges on said looper and said knife cooperate to cut a loop disposed on said looper, said cutting apparatus further including a knife supporting block having a substantially rectangular cross-section and having a truncated cavity disposed therein with the side walls of said cavity being disposed at an acute angle with respect to the base wall of said cavity, and means for clamping said substantially rectangular knife in said cavity with its end walls in clamping relationship with the side walls of said cavity whereby said knife is clamped in a wedging relationship with said cavity side walls. 